FRIGIDARIUM  , the Latin

term (from frigidus, cold) applied to the open area of the Roman thermae, in which there was generally a cold swimming bath, and sometimes to the bath (see BATHS) . From the description given by Aelius Spartianus (A.D . 297) it would seem that portions of the frigidarium were covered over by a ceiling formed of interlaced bars of gilt bronze, and this statement has been to a certain extent substantiated by the discovery of many tons of T-shaped iron found in the excavations under the paving of the frigidarium of the thermae of Caracalla . Dr J . H . Middleton in The Remains of Ancient Rome (1892) points out that in the part of the enclosure walls are deep sinkings to receive the ends of the great girders . He suggests that the panels of the lattice-work ceiling were filled in with concrete made of light pumice stone .